Chandler River
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TMDL Summary Appendix 666---111777 Chandler River Watershed Description Waterbody Facts This TMDL applies to a 27.19 mile section of the Chandler River, Segment ID: including its eastern branch, located in the Towns of Duram, ME0106000102_603R02 Pownal and North Yarmouth, Maine. The headwaters of the Town: Duram, Pownal, Chandler River are at the outlet of Runaround Pond in Durham. North Yarmouth, ME The river flows south, crossing Runaround Pond Road, then County: Cumberland through a wooded area before crossing Poland Range Road, Lawrence Road, Elmwood Road, and Chadsey Road, in an area of Impaired Segment mixed forest, agriculture and residential development. The river Length: 27.19 miles continues south, crossing Milliken Road, and meets with the East Classification: Class B Branch before flowing south to its convergence with the Royal River in Gray. The East Branch originates in a wetland complex in Direct Watershed: 51.89 2 Durham. The river flows south through a predominantly forested mi (33,210 acres) area before crossing Quaker Meeting House Road, Brown Road, Impairment Listing Poland Range Road, Tuttle Road and Elmwood Road. The river Cause: Dissolved Oxygen then crosses Hodsdon Road, flows north across Hallowell Road and then south again. Downstream of the West Pownal Road crossing, Watershed Agricultural the East Branch meets the main stem of the Chandler River. Land Use: 14.3% The Chandler River watershed covers an area of 51.89 square Major Drainage Basin: miles. The majority of the watershed is located with0in the Town Presumpscot River of Pownal, however, smaller portions of the watershed lie within the surrounding towns of Auburn, New Gloucester, Durham, Brunswick, Freeport, Gray, and North Yarmouth. Runoff from agricultural land along Tuttle Road is likely the largest source of nonpoint source (NPS) pollution to the Chandler River. Runoff from cultivated lands, active hay lands, and pasture can transport nitrogen and phosphorus to the nearest section of the stream. The Chandler River watershed is predominately non-developed (95.8%). Forested areas (74.1%) within the watershed absorb and filter pollutants helping protect both water quality in the stream and stream channel stability. Wetlands (7%) may also help filter nutrients. Non-forested areas within the watershed are predominantly agricultural (14.3%). Developed areas (4.2%) with impervious surfaces may impact water quality. The Chandler River including its East Branch is on Maine’s 303(d) Watershed Land Uses list of Impaired Streams (Maine DEP, 2013). Definitions Agriculture • Total Maximum Daily Load (TMDL) represents the total amount Forest of pollutants that a waterbody can receive and still meet water Wetland quality standards. Developed • Nonpoint Source Pollution refers to pollution that comes from many diffuse sources across the landscape, and is typically transported by rain or snowmelt runoff. Maine Statewide TMDL for NPS Pollution June 2016 Figure 1: Land Use in the Chandler River Watershed WHY IS A TMDL ASSESSMENT NEEDED ? The Chandler River including its East Branch, a Class B freshwater stream, has been assessed by Maine DEP as not meeting water quality standards for the designated use of aquatic life, and placed on the 303(d) list of impaired waters under the Clean Water Act. The Clean Water Act requires that all 303(d)-listed waters undergo a TMDL assessment that describes the impairments and establishes a target to guide the measures needed to restore water quality. The goal is for all waterbodies to comply with state water quality standards. Agriculture in the Chandler River watershed makes up about 14% of the total land area, more than three times the area of Chandler River (East Branch) at Tuttle Road. Photo: FB Environmental developed land which accounts for about 4% of total land area (Figure 1). Agriculture is therefore likely to be the largest contributor of sediment and nutrient enrichment to the stream. The close proximity of many agricultural lands to the stream further increases APPENDIX 6-17 2 Maine Statewide TMDL for NPS Pollution June 2016 the likelihood that nutrients from disturbed soils, manure, and fertilizers will reach the stream. Along Tuttle Road, in particular, heavy erosion was documented as a result of livestock in the stream. WATER QUALITY DATA ANALYSIS Maine DEP uses a variety of data types to measure the ability of a stream to adequately support aquatic life, including; dissolved oxygen, benthic macroinvertebrates, and periphyton (algae). The aquatic life impairment in Chandler River is based on historic dissolved oxygen data. TMDL ASSESSMENT APPROACH : NUTRIENT MODELING OF IMPAIRED AND ATTAINMENT STREAMS NPS pollution is difficult to measure directly, because it comes from many diffuse sources spread across the landscape. For this reason, a nutrient loading model, MapShed, was used to estimate the sources of pollution based on well-established hydrological equations; detailed maps of soil, land use, and slope; many years of daily weather data; and direct observations of agriculture and other land uses within the watershed. The nutrient loading estimates for the impaired stream were compared to similar estimates for five non- impaired (attainment) streams of similar watershed land uses across the state. The TMDL for the impaired stream was set as the mean nutrient loading estimate of these attainment stream watersheds, and units of mass per unit watershed area per year (kg/ha/year) were used. The difference in loading estimates between the impaired and attainment watersheds represents the percent reduction in nutrient loading required under this TMDL. The attainment streams and their nutrient and sediment loading estimates and TMDL are presented below in Table 1. Table 1: Numeric Targets for Pollutant Loading Based on MapShed Model Outputs for Attainment Streams TP load TN load Sediment load Attainment Streams Town (kg/ha/yr) (kg/ha/yr) (1000 kg/ha/yr) Martin Stream Fairfield 0.14 3.4 0.008 Footman Brook Exeter 0.33 6.4 0.058 Upper Kenduskeag Stream Corinth 0.29 5.6 0.047 Upper Pleasant River Gray 0.22 4.6 0.016 Moose Brook Houlton 0.25 5.9 0.022 Total Maximum Daily Load 0.24 5.2 0.030 APPENDIX 6-17 3 Maine Statewide TMDL for NPS Pollution June 2016 RAPID WATERSHED ASSESSMENT Habitat Assessment A Habitat Assessment survey was conducted on both the impaired and attainment streams. The assessment approach is based on the Rapid Bioassessment Protocols for Use in Wadeable Streams and Rivers (Barbour et al., 1999), which integrates various parameters relating to the structure of physical habitat. The habitat assessments include a general description of the site and physical characterization and visual assessment of in-stream and riparian habitat quality. Based on Rapid Bioassessment protocols for low gradient streams, the Chandler River received a score of 171 out of a total 200 for quality of habitat. Higher scores indicate better habitat. The range of habitat assessment scores for attainment streams was 155 to 179. RAPID HABITAT ASESSMENT SCORES The habitat assessment was conducted on a for Attainment and Impaired Streams relatively short sample reach (about 100-200 meters 200 for a typical small stream), and was located near the most downstream Maine DEP sample station. For 190 both impaired and attainment streams, the assessment location was usually near a road 180 crossing for ease of access. In the Chandler River watershed, the downstream sample station was 170 located in a forested portion of the stream with a thick buffer. Although there is some agriculture 160 Attainment within the Chandler River watershed, a majority of Impaired the stream flows within forested areas. 150 Figure 2 (right) shows the range of habitat Habitat Score Chandler 140 assessment scores for all attainment and impaired River streams, as well as for the Chandler River. The overlapping attainment and impaired stream scores 130 indicate that factors other than habitat should be considered when addressing the impairments in the 120 Chandler River. Consideration should be given to major “hot spots” in the Chandler River watershed 110 as potential sources of NPS pollution contributing to the water quality impairment. 100 Figure 2: Habitat Assessment Scores Pollution Source Identification Pollution source identification assessments were conducted for both Chandler River (impaired) and the attainment streams. The source identification component of this study is based on an abbreviated version of the Center for Watershed Protection’s Unified Subwatershed and Site Reconnaissance method (Wright, et al., 2005). The abbreviated method includes both a desktop and field component. The desktop assessment consists of generating and reviewing maps of the watershed boundary, roads, land use and satellite imagery, and then identifying potential NPS pollution locations, such as road crossings, agricultural fields, and large areas of bare soil. When available, multiple sources of satellite imagery APPENDIX 6-17 4 Maine Statewide TMDL for NPS Pollution June 2016 were reviewed. Occasionally, the high resolution of the imagery allowed for observations of livestock, row crops, eroding stream banks, sediment laden water, junkyards, and other potential NPS concerns that could affect stream quality. As many potential pollution sources as possible were visited, assessed and documented in the field. Field visits were limited to NPS sites that were visible from roads or a short walk from a roadway. Neighborhoods were assessed for NPS pollution at the whole neighborhood level including streets and storm drains (where applicable). The assessment does not include a scoring component, but does include a detailed summary of findings and a map indicating documented NPS sites throughout the watershed. The watershed source assessment for the Chandler River was completed on July 6, 2012. In-field observations of erosion, lack of vegetated stream buffer, extensive impervious surfaces, high-density neighborhoods and agricultural activities were documented throughout the watershed (Table 1, Figure 3). Table 2: Pollution Source ID Assessment for the Chandler River Watershed Potential Source ID# Location Type Notes Road • Moderate erosion observed at road crossing.